Carbon ignition

In the 1960s there were attempts to use a moving bed of carbon to remove sulphur dioxide from flue gas on a pilot scale. As described by Katell(46) and Cartelyou(47), this Reinluft process was abandoned because of the problems caused by the carbon igniting in the presence of oxygen. 

Saio, Kato, and Nomoto (1988) recently examined under what conditions a massive star undergoes a blue-red-blue evolution. The evolution of a star of initial mass 20 M0 star in the HR diagram is shown in Figure 1 from the zero-age main-sequence through carbon ignition at the center. The metallicity in the envelope was assumed to be Z = 0.005 and the Schwarzschild criterion was adopted. The star shows the three types of evolutionary path (A, B, C) depending on the mass loss, metallicity, and the change in the helium abundance Y in the envelope. 

Activated carbon ignites immediately in the gas, mixtures with methane ignite, and those with carbon monoxide ignite on warming, while those with hydrogen explode on heating or sparking. 

Lead carbonate ignites and burns fiercely in fluorine.6... 

Combustion Rate of Carbon—Eq (12-18) can hardly be expected to hold at ignition temperatures. Indeed it is doubtful whether it will hold at temperatures much above 400 deg C even in the case of anthracite coal. Above this point the carbon ignites and a completely new set of conditions pertains to the problem. Studies on the combustion rate of carbon particles have been studied in considerable detail by several investigators. The general method used was described by Parker and Hottel (1936). The device used consists of a furnace in which is suspended a cylindrical rod of carbon 2.5 cm in diameter with a hemispherical end. The rod is mounted on a porcelain tube and suspended from one arm of a balance so that the hemispherical end is downward in the furnace. In this way loss of weight is easily determined. The surface of the specimen is also capable of measurement. Known volumes of air heated to the required temperatures are then made to flow past the carbon, and by means of a small quartz sampling-tube (which can be adjusted at any distance from the specimen) samples are withdrawn for analysis. In this way samples of air may -be analyzed for the amount of carbon dioxide and oxygen present at any distance from the heated particle-surface. 

Flammable liquid when exposed to heat or flame can react with oxidizing materials. Moderate explosion hazard when exposed to heat or flame or by chemical reaction. An exothermic polymerization of almost explosive violence can occur upon contact with strong mineral acids or alkalies. Keep away from heat and open flames. Mixture with sodium hydrogen carbonate ignites spontaneously. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. 

Complementary tests were carried out for studying the regeneration process of ceramic sintered filter samples by uncatalysed and catalysed combustion of the accumulated carbon particles. With respect to the uncatalysed case, the presence of catalyst reduces the carbon ignition temperature so favouring spontaneous filter regeneration. However, the catalyst activity appears to be lower than that observed in the reactivity tests. 

For stars more massive than eight times the mass of the Sun, carbon ignites before degeneracy pressure becomes dominant. The key carbon burning reaction is... 

Ignition Activated carbons ignite at lower temperature than oxide carriers. Activated carbons show an ignition temperature of about 200°C (chemical activated carbons) up to 500°C (steam activated carbons). This characteristics is used advantageously by burning the carrier to reclaim the precious metal. 

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